Whisk together marmalade, lemon juice, and walnut oil; salt to taste. Add banana and sugar; set aside. Arrange fruit slices on individual plates and sprinkle with POM Wonderful Pomegranate Arils. Spoon banana vinaigrette on top of fruit. If desired, mix ricotta cheese and sour cream; dollop mixture onto each plate.
Vinaigrette:
Fruit salad: